Biology 2483A Lecture Notes - Lecture 20: Ecological Pyramid, Steller Sea Lion, Food Quality

• School: Western University
• Department: Biology
• Course: Biology 2483A
• Professor: Hugh Henry

Document Summary

The ecological roles of organisms are determined by trophic interactions - what they eat and what eats them. This determines the influence of an organism on the movement of energy and nutrients through an ecosystem. Tropic levels describe the feeding positive of groups of organisms in ecosystems. Detritiovers function as a second tropic level organisms. All organisms are either consumed by other organisms or enter the pool of enter the pool of dead organic matter (detritus). In terrestrial ecosystem only a small portion of the biomass is consumed, and most of the enrgy flow passes through the detritus. Most energy flow is through dead organic material. In aquatic system most of the organisms are eaten by living organisms. Dead organisms and feces are consumed by organisms called detritivores (primarily bacteria and fungi) Detritus is considered part of the first trophic level, and detritivores are part the second level.